Leukemia is a malignant tumor that originates in the hematopoietic system, and its incidence continues to increase. Recent studies have shown that gut microbiota and its metabolites play an important role in the occurrence and development of leukemia and its complications. The imbalance of intestinal flora may lead to decreased immune function and inflammatory response, becoming one of the key factors promoting the development of leukemia and its complications. It has been found that bacteria such as faecalis and Enterococcus and metabolites such as bile acids, short-chain fatty acids and hydrogen sulfide have a significant impact on the development and prognosis of leukemia, and the use of fecal flora transplantation and probiotics has shown safety and effectiveness in clinical studies of leukemia. In this paper, the role of intestinal flora and its metabolites in the occurrence, development and prognosis of leukemia was reviewed, and the potential of traditional Chinese medicine to regulate intestinal flora and its metabolites in the treatment of leukemia and its complications was discussed.